\part{Brooks's Law Simulation}
\begin{figure}[H]
\begin{center}
\pgfimage[width=0.6\textheight]{Grafiken/brooksLaw}
\end{center}
\caption[Brooks's Law]{Brooks's Law}\label{Brooks Law2}
\end{figure}
\section{Default Scenario}
% Introduction Vensim:
% 100 people @ work
% 8/10 unit tests rdy
% Work to be done 200h (1000 h in total)
% Relative progress 80%
In most cases it is impossible to describe the concrete values a feedback relationship has. For this example we assumed values that were reasonable and easy to understand. Even though we tried to fit an example that is likely to appear in reality.

\paragraph{Number of People} At the beginning state the project has 100 team members assigned. The model offers the ability of adding peoples to the project which affects the other states.
\paragraph{Productive Work finished} Is measured in successful unit tests. At
the beginning 8 of 10. When a new team member will be added to the
project without any intensive planning, one additional unit test will fail.
Imagine a new employee that has to work on critical tasks without knowledge of the domain.
Sooner or later he is going to crash his assigned topic.
\paragraph{Amount of Work to be done} There are 200 hours left in the project
of a total amount of 1000 hours, which represents the finished project. When adding a new employee to the project the experienced workers have to train him and their work load will rise. This amount is calculated with 5 hours per new worker.
\paragraph{Relative Progress} The Relative progress is measured with 80\% since there is the will to get finished soon much earlier. This value is altered by both the \textit{Amount of Work to be done} and the \textit{Productive Work finished} feedback impact. The value is calculated by:

\begin{displaymath}Relative Progress = \frac{(\frac{Productive Work
Finished}{10} * 100) + (\frac{1000 - Amount Of Work To Be Done}{1000}*100)}{2}
\end{displaymath}

Scope of this example is only one week, since feedback loops over weeks are very linear, when their input is not altered during the process.
 
% Per additional person:
% Work to be done: additional 10h per week for training   (+ (Number of People*10))
% Unit tests: - 1 per week                                (- Number of People)
% 
% Relative Progress: average value of percentage „productive work“ and „amount of work“
% ((Prodcutive Work finished*10 + (((1000 - Amount of Work to be done)/1000)*100))/2)

\section{Scenario with Decision Points}
The key statement of Weinberg is that we will have the ability to decide if the human decision points are detected. In his critique to Brooks's Law he describes that the addition of sheer working power will fulfill the habits of the law, but if manager actions go more sensible into feedback at specific points the relative progress will rise as intended.\\\\
In our example this chance is described with the separation of unexperienced
from experienced workers. If so, there will be no additional workload on the
employees by training the new ones. Trainees are not assigned with high detailed work in the project domain, instead they have to assist the old workers in their work, by doing low-level documenting and testing. Since the new ones are not engaged in code development they will also not harm the number of completed unit tests.\\\\ Therefore, the \textit{Work Load} is lowered (instead of risen) while the \textit{Productive Work finished} stays the same, which results in a slowly but steadily increasing relative progress.
% Vensim Part 2:
% Adding people planned:
% - Productive work untouched
% - Amount of work reduced by 2 hours per week because of small assisting jobs like documention, etc.
% - Relative Progress plus 0.5 percent per week

\section{Simulation}

The simulations below show the above described effects of adding new workers to
a project.\\

First new employees are fully integrated into sensitive processes which results
in failures of unit tests and additional workload for training of the new
workers. The total project status is going down. Only 3 new workers may decrease the
relative progress by about 15\% within 1 week.\\

The second example (figures \ref{Brooks Law Sim 03} and \ref{Brooks Law Sim
04}) shows the effects if managers choose to take their decision point and add
the unexperienced people planned to the project. Which implies their sensitive
engagement in low level activities.\\
 
\begin{figure}[H]
\begin{center}\pgfimage[width=0.8\textwidth]{Vensim/brooks_law_sim_add_people_not_planned_01}\end{center}
\caption[Brooks's Law Simulation - Adding people not planned (Model)]{Adding
people not planned (Model)}\label{Brooks Law Sim 01}
\end{figure}\
\begin{figure}[H]
\begin{center}\pgfimage[width=0.8\textwidth]{Vensim/brooks_law_sim_add_people_not_planned_02}\end{center}
\caption[Brooks's Law Simulation - Adding people not planned (Graphs)]{Adding
people not planned (Graphs)}\label{Brooks Law Sim 01}
\end{figure}

\begin{figure}[H]
\begin{center}\pgfimage[width=0.8\textwidth]{Vensim/brooks_law_sim_add_people_planned_01}\end{center}
\caption[Brooks's Law Simulation - Adding people planned (Model)]{Adding people
planned (Model)}\label{Brooks Law Sim 03}
\end{figure}
\begin{figure}[H]
\begin{center}\pgfimage[width=0.8\textwidth]{Vensim/brooks_law_sim_add_people_planned_02}\end{center}
\caption[Brooks's Law Simulation - Adding people planned (Graphs)]{Adding people
planned (Graphs)}\label{Brooks Law Sim 04}
\end{figure}

\newpage

\section{Summary}
%Analyze the behavior of a system, its nonlinearities and loops and plan how to
%make effective interventions using Feedback Models


% First you have to know why you need to build a model of your system and how to
% build it.
% As a manager in charge of controlling a system you have to know what kind of
% circles in your system are working for you and what circles are working against
% you. You will find out that not every action can be undone and it is hard to
% decide between effects and their cause.\\
% 
% Second you have to realize that a manager is not a helpless person bound by
% rules like Brooks's Law. `Adding manpower to a late software project makes it
% later.` is not the final state. In your system are a lot of decision points
% where you have the opportunity to intervene.\\
% 
% Third, interchange with your employees will help you to get the important
% feedback, that helps you to react in time and very precise.\\
% 
% Finally, simulations of your model can help you to extend your knowledge how
% even small changes to your system will effect the final output and
% what impact these changes have on other parts within the system.\\  

Inside a living system are processes at work. To understand their coherence
and their consequences it is important to build correct models.
Instability is one of many threats to this system and control actions of
managers a way to handle them.\\

First, a manager has to know how to model a system. The Feedback Control Model
and the Diagram of Effects are his tools to work with. A model will allow him
to detect positive and negative feedback loops inside the system. This enables
him to find out what kind of circles in the system are working for him and
what circles are working against him.
Also important is the fact, that not every action can be undone and it is hard
to decide between effects and their cause.\\

Second, he has to realize that he is not a helpless person bound by
rules like Brooks's Law. `Adding manpower to a late software project makes it
later.` is not the final state. By building a correct model of the system he
might discover a lot of decision points where he has the opportunity to
intervene.\\

Third, the interchange with employees will help to get important
feedback, that will additionally help to react in time and very precise.\\

Finally, building a simulation of the model can help to extend the 
knowledge how far even small changes to the system will effect the final output
and what impact these changes will have on other parts within the system.\\

But without a strong and complete model all these assumptions are worthless. You have to extract your own model from the reality of your organization and discover your ability of intervention and feedback.\\

%\note[item]{Notizen}

